A severe thunderstorm is moving through the Hawke's Bay, drowning the region in rain. A school has been evacuated and roads closed - and Civil Defence is issuing evacuation advice.

What you need to know:

Flash floods are hitting the region

At least five families have been trapped. Others have been evacuated in time

Roads and railways have been washed away

Heavy rain is expected until around midnight tonight

These live updates have now ended.

4:15pm – Blue Duck Station takes matters into its own hands after slips

Whanganui farmer Dan Steel says their power lines are down, water supply is affected and roads washed away.

“[We’ve] got precision helicopters flying over from Taranaki, they’re bringing four generators and some supplies so we’ve got about 100 people down on the station currently,” he told Newshub.

4:10pm – Civil Defence staff concerned by Eskdale river levels

Civil Defence group manager Ian Macdonald says they're keeping an eye on the Eskdale River, north of Napier.

“The rest of the rivers in the Hawkes bay are actually in pretty good condition we have no concerns. It’s only the Eskdale River which is quite a short and steep catchment.”

4.01pm - More rain forecast for Hawke’s Bay

MetService says more localised thunderstorms and downpours are possible for Hawke's Bay tonight.

Rain gauges in the region captured over 130 millimetres of rain on Thursday.

“There’s a few places up in the ranges that have reported 130, 140 millimetres and I have heard that there is a council rain gauge that recorded 55 millimetres in an hour,” MetService spokesperson Lisa Murray told Newshub.

2:58pm - SH5 Napier to Taupo and SH2 Eskdale to Tutira reopened

The NZTA is urging the public to drive carefully. Civil Defence is advising the public to avoid driving unnecessarily.

2:20pm – Photo shows the extent of flooding at an orchard in lower Esk Valley

1:54pm - Whanganui considers implementing flood protection barriers

Horizons Regional Council has announced on Twitter crews have been put on standby and the Kowhai Park flood barrier may potentially be put into operation.

1:20pm - Video shows raging power of river in flood

1:05pm - Civil Defence's evacuation check list

Hawke's Bay Civil Defence has put out a check list for people near the Esk River who are planning to self-evacuate their household and animals.

"Here is a check list of things you should consider before self-evacuating," it says.

"We will continue to provide updates so keep up to date with the latest information."

The list includes making a plan for pets, contacting loved ones and having essential items.

12:50pm -More road closures

The NZTA is warning of further road closures across the region. The Napier to Taupo road, State Highway 5, is closed after heavy rain caused slips and flooding.

The NZTA says that it is not clear when the Napier-Taupo Road will re-open. A detour route via Taupo and Palmerston North will add four to five hours to the journey.

Other road closures:

State Highway 45, between New Plymouth and Omata, due to a fallen tree

SH43, between Taumarunui and Whangamomona, is closed due to slips - the detour is via State Highway 3 and 4